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Mechanical Engineering
Mechanical Engineering is a branch of engineering that encompasses the generation and application of heat and mechanical power and the design, production, and use of machines and tools. Mechanical engineering involves application of the principles of dynamics, control, thermodynamics and heat transfer, fluid mechanics, strength of materials, materials science, electronics, and mathematics.
10,989 Questions
What is critical in stress intensity?
Stress intensity is related to product of stress and flaw size for materials. If stress is increased to critical, this results in catastrophic failure. The critical stress intensity factor KIc is a property of the material.
KIc = Strength x sqrt(flaw) x geometry factor
Another term for this is infrasonic, and it means pertaining to below hearing. There natural frequencies that humans can hear which are high: 20,000 Hz and low: 20 Hz. An average human cannot hear sounds below the frequency of 20 Hz. That is subsonic. Subsonic is a term also applied to aircraft that travel at speeds less than the speed of sound. Supersonic means it travels faster than the speed of sound.
Economizer is an accessory of boiler that recovers the waste heat from the flue gas blown out of the boiler. Thus it actually "economizes" the operational cost or in other words, improves the efficiency of fuel utilisation in the boiler.
The temperature of the flue gases ( the mixture of burnt fuel & air ) depends up on the steam pressure ( temperature more precisely ). Higher the steam pressure generated, the higher is the flue gas temperature. Economizer is a heat exchanger which exchanges heat between water ( which is fed in to the boiler ) & the flue gas. It means it increases the temperature of the feed water using the otherwise wasted heat of the flue gas. So the water entering the boiler has higher temperature compared to the one without this economizer. This higher temperature of water requires less amount of heat to generate steam so the operation becomes "economical". Similarly the economizer can also work to heat up the air entering the boiler through the flue gas heat, instead of heating the water.
Could you make a plane motionless in air?
Yes. Example: When the aeroplane's method of propulsion would give it a forward velocity but that velocity equels the speed of a headwind. (The two speeds wouldn't be exactly equel due to the inherent resistance of the aeroplane's structure, but hey... that's just quibbling... ;-)
What happen to Stanley A Myers patent?
it's more alive than ever - everyone is doing his research. trying to augment fuel for their vehicles, let me explain generating highly explosive browns gas (a molecule of two hydrogen atoms sharing an electron) from water ( two hydrogen atoms sharing the electrons of one oxygen atom) by electrolysis is a very common technique especially in welding (hydrogen flame will instantly melt steel) although it consume considerable electricity. One of Myers main points was to apply pulse width modulation (a series of small electrical pulses) to the electrolysis process to enhance yields of hydrogen while lowering the amperage. This allowed him to miniaturize the device suitable for vehicles, this is a "no free energy" device any more than a computer is gremlins and magic. And I believe his work is parallel to deriving the modern transistor from the vacuum tube and will be instrumental to relieving the 850,000,000 internal combustions engines ICE from the environmental disaster of petroleum and ethanol. you can read more about browns gas here http://www.brownsgas.com you can read more about his patents here. http://www.rexresearch.com/meyerhy/meyerhy.htm wozza.xing www.hhoforums.com
Difference between heat rejection and heat absoarb in refrigerator?
Heat is absorbed by the refrigerant liquid inside the fridge, and rejected by the heat exchanger on the back of it.
What engines are faster electrical or pneumatic systems?
The amount speed put out from any prime mover depends on the amount of energy put into the system. Hence there can be no absolute answer to your question.
How and where would you install a shut-off valve on a wall-mount faucet?
I take it that you are mounting it out side, put the shut off valve in side, with a drain on it,
What is the tank with spouts called in sewage works?
"Tank with spouts " may refer to either the 'settling tank' or the 'pump tank' in most sewage systems.
What is a steering wheel made of?
Most vehicular steering wheels are generally made of plastic over a steel "frame" or core. Certainly there are many custom or racing variations.
Why is a diamond pin locator used with a round pin locator?
It's more difficult to mount a workpiece on two round pins than on a round and a diamond. A diamond pin is meant to handle the variation (tolerance) of the distance between the two locating holes.
Two round locating holes with diameters closely sized to the locating holes diameters may not always accept the allowable distance variation between them.
What valves preffered in the upstream and downstream of a control valve ball valve or globe valve?
That would depend on the application such as high steam pressure and if throttling is needed
Is the block numbers on a 67 350 motor 3970010?
3970010 is a 327 in the years from 1967-1969 and 350 from 1976-1979
What if the spinning wheel had not been invented?
Then we probably would not have the sewing machine. The sewing machine is a rise up of the spinning wheel.
Distinguish between First Angle Projection method and third angle projection method?
right side view draw in left side and left side view draw in right side is called third angle projection
When would you use a one system pulley?
I think you mean "a one pulley system." When you want to pull in the opposite direction you want the object to move. If you tow a log behind a vehicle you don't use one so the log follows the car. But, if you wanted to lift that log you would throw the rope over a tree branch or pulley to lift it into the air as you pull down, thus using your weight with gravity to help lift the log.
However, by attaching the pulley to the tree branch, you don't gain any mechanical advantage other than using gravity with pulling down.
If, on the other hand, you attach your one pulley to the log, attach one end of the rope to the tree branch, and lift up with the other end you do gain mechanical advantage with it requiring half the force of the previous example of pulling down. But, you are limited by working against gravity and you can only lift as high as you are standing.
How is a submarine able to submerge and surface?
Submarines have ballast tanks. The tanks can hold air, or they can be "vented" and water can flow into them and fill them completely. When the tanks are full of air, the submarine is buoyant and floats. When the main vents are opened, the tanks are flooded and the submarine submerges. When the submarine is submerged and wants to surface, air can be injected at high pressure into the ballast tanks to force out water and again make the submarine buoyant and cause it to rise to the surface and float. In practice, when a submarine surfaces, it doesn't use a lot of air from its high pressure air tanks to "blow the ballast tanks" because it takes a long time to pump up the high pressure air tanks again. What happens is that all the ballast tanks are given a "good shot" of high pressure air (a few seconds), and then the planes are used in conjunction with the screw (which some call a propeller) to actually drive a submarine to the surface. Once there, something called a low pressure blower system can be used to finish blowing the ballast tanks (while the high pressure air compressors are running to pump the high pressure air tanks back up). When as submarine is submerged, the trick is to keep in neutrally buoyant and "balanced" or trimmed so that it is "level" in the water (has a "zero bubble"). There are axillary tanks aboard that allow trimming the boat, and that are used to set up neutral buoyancy. When a boat is properly trimmed and neutrally buoyant, it can be moved most efficiently through the water. The planes, which are used to "steer" the ship vertically, will be at zero and the boat will hold its depth with a zero bubble. There is a bit more to this, but the basics can easily be grasped and are covered here. A link is provided to our friends at Wikipedia who have posted an article on submarines, and it contains information on submerging and surfacing. Knowledge there is free, and you can use the post to check facts and learn more.
Normally you would specify a motor to do a particular job by the mechanical power output you require.
A motor takes electrical power "in" and produces mechanical power "out".
Read whatever it says on the motor's rating plate or user-guide.
The mechanical energy output of a motor is measured in various units around the world: for example in watts, horsepower (or brake horsepower).
Another answer
The above answer is quite correct in stating that a motor's output power is its rated power as it's a guide to how much load it can drive.
Power is simply a rate - the rate of transfer of energy. The horsepower is the Imperial unit of power, whereas the watt is the SI unit of power. In the US the output power of a motor is typically still measured in horsepower whereas in Europe the use of horsepower is almost obsolete, except for small "fractional horsepower" electric motors, and both the input power and the output power of a motor are measured in watts or, more likely, kilowatts.
Converts chemical potential energy in the fuel to mechanical work at the shaft.
How do you calculate Wind turbine torque?
Measure the rpm & calculate the torque as power divided by angular velocity
